For the salad:
5 oz baby arugula (I've never been able to find this so I use regular arugula)
2 Tbsp olive oil
2 Tbsp fresh lemon juice, plus lemon wedges for serving
1 small red onion, halved lengthwise and thinly sliced

Directions:
Preheat oven to 425º. On a rimmed baking sheet, toss breadcrumbs and oil until well combined; spread on sheet. Cook until golden brown, 2–3 minutes. Transfer to a medium bowl.
Place flour and eggs in separate bowls; season with salt and pepper. Place a rack (like a metal cookie cooling rack) on another rimmed baking sheet.
One at a time, place chicken breasts between two large pieces of plastic wrap or a ziplock bag. Using a meat mallet or bottom of a small heavy pan, pound until 1/4–1/2 inch thick. Coat chicken on both sides with flour (shaking off excess), then dip in eggs (allowing excess to drip off); dredge in breadcrumbs, pressing firmly to adhere.
Place on rack and bake chicken, without turning, until opaque throughout, 10 to 15 minutes.
When chicken is almost finished cooking, whisk together remaining 2 tablespoons oil and lemon juice in a bowl; season with salt and pepper. Add arugula and onion; toss. Top chicken with salad; serve with lemon wedges on the side.